theme 4. stock enhancement 1. introduction 2. us perspective on history, pitfalls and progress...

Theme 4. Stock Enhancement 1. Introduction 2. US Perspective on History, Pitfalls and Progress Kenneth M. Leber

As population growth continues to increase, how will we sustain fisheries? Harvest Management: Control fishing catch & effort seasonal closures, size and catch limitations, area closures, incentives (catch shares), number of angler licenses (limited entry), spatial planning Harvest Management: Control fishing catch & effort seasonal closures, size and catch limitations, area closures, incentives (catch shares), number of angler licenses (limited entry), spatial planning Habitat Management: We can identify, protect and restore essential habitat EFH, MPAs, spatial planning, habitat restoration, artificial reefs Habitat Management: We can identify, protect and restore essential habitat EFH, MPAs, spatial planning, habitat restoration, artificial reefs Marine Fisheries Enhancement: Fishery managers can boost abundance by stocking hatchery-reared fish to increase the number of young fish (new recruits) in the population in certain situations Marine Fisheries Enhancement: Fishery managers can boost abundance by stocking hatchery-reared fish to increase the number of young fish (new recruits) in the population in certain situations

Coupling Fisheries Management and Aquaculture Marine fisheries enhancement Types: Marine fisheries enhancement Types: Stock Enhancement: release of cultured organisms into wild populations to increase the natural supply of juveniles Stock Enhancement: release of cultured organisms into wild populations to increase the natural supply of juveniles Restocking: release of cultured organisms into wild populations to help rebuild depleted wild stock to higher abundance Restocking: release of cultured organisms into wild populations to help rebuild depleted wild stock to higher abundance Sea Ranching: release of cultured juveniles into the ocean for harvest at a larger size (put-grow-take) Sea Ranching: release of cultured juveniles into the ocean for harvest at a larger size (put-grow-take) (Bell et al., 2008. Reviews in Fisheries Science, 16(1):1-9) 3 rd ISSESR

Historical Background: Evaluation of Marine Stock Enhancement Early Constraints to Successful Enhancement Early Constraints to Successful Enhancement Aquaculture constraints Assessment constraints Pioneering Work to Quantify Stocking Effects Pioneering Work to Quantify Stocking Effects Tsukamoto; Kitada; Tanaka; Yamashita; colleagues in Japan Svsand, Jrstad, Kristiansen and colleagues in Norway Polovina; Stoner; Willis; Kent; Leber; Blankenship; Smith; et.al. in US Bannister and colleagues in the UK Stttrup and colleagues in Denmark Bell in Solomon Islands Rimmer, Russell and colleagues in Australia Recent Approach Recent Approach Improved Experimental Design Comprehensive Assessment Efforts 1880s 1980s 1990s 2000s

Science & Fishery Perspective- Driven Policy Development New research in early 1990s generated WAS & EAS special sessions at their annual conferences -- on marine stock enhancement New research in early 1990s generated WAS & EAS special sessions at their annual conferences -- on marine stock enhancement International Working Group on Stock Enhancement formed in 1993 in Spain International Working Group on Stock Enhancement formed in 1993 in Spain Platform Paper: Responsible Approach Presented at 1994 AFS Symposium Presented at 1994 AFS Symposium International Symposium on Stock Enhancement and Sea Ranching (ISSESR): every 4-5 years International Symposium on Stock Enhancement and Sea Ranching (ISSESR): every 4-5 years Norway-1997, Japan-2002, US-2006, China-2011, (Australia-2015...)

A Responsible Approach to Marine Stock Enhancement * Stay Within Context of Fisheries Management Plan: Stay Within Context of Fisheries Management Plan: 1. Prioritize Species for Enhancement 2. Make Stocking Plan that Fits with and Helps Achieve the Goals of the Fishery Management Plan and Identify the Expectations Develop Sound Enhancement Strategy: Develop Sound Enhancement Strategy: 3. Define Quantitative Measures of Success 4. Use Genetic Resource Mgmt. to Prevent Deleterious Effects 5. Use Disease and Health Management 6. Consider Ecological, Biological, & Life-History Patterns 7. Identify Hatchery Fish & Assess Stocking Effects 8. Use an Empirical Process to Define Optimal Release Strategies 9. Identify Economic & Policy Guidelines 10. Use Adaptive Management (* Blankenship & Leber, 1995. Am. Fish. Soc. Symposium 15:67-175) PDF is online at www.StockEnhancement.org/science/publications.html PDF is online at www.StockEnhancement.org/science/publications.html (Spawned by Lee Blankenship, Devin Bartley, Don Kent, Ken Leber, Stan Moberly, Terje Svsand, Katsumi Tsukamoto [and Rich Lincoln])

Science & Fishery Perspective- Where Hatcheries Can Go Wrong 1. Replacement of wild with hatchery recruits, with no net increase in total stock 2. Unregulated fishing effort responses to presence of hatchery fish can cause overfishing of wild stock 3. Overexploitation of forage resource base for the stocked species 4. Genetic impacts on the long-term viability of the wild stock Stress that it is critical to monitor the impacts of enhancement as the program develops to have evidence in hand if debate about effectiveness surfaces (Carl Walters & Steve Martell, 2004)

Updated Responsible Approach to Marine Stock Enhancement * (Lorenzen, Leber, and Blankenship. 2010. Rev. Fish. Sci. 18(2):189-210)

Most Enhancements are Weak in 5 Areas Lack of a clear fishery-management perspective Lack of a clear fishery-management perspective Fishery stock assessments & modeling are integral to exploring the potential of stocking, yet both are found lacking in most stock enhancement efforts Fishery stock assessments & modeling are integral to exploring the potential of stocking, yet both are found lacking in most stock enhancement efforts Establishing an institutional framework for enhancements is largely ignored Establishing an institutional framework for enhancements is largely ignored Involvement of stakeholders in planning and execution of stocking programs is key from the start, but is rarely an integral part Involvement of stakeholders in planning and execution of stocking programs is key from the start, but is rarely an integral part Adaptive management is not well integrated into enhancement plans Adaptive management is not well integrated into enhancement plans

Updated Responsible Approach to Marine Stock Enhancement Stage 1: Initial Appraisal & Goal Setting 1. Understand the role of enhancement within the fishery system 2. Engage stakeholders & develop a rigorous decision-making process 3. Quantitatively assess contributions of enhancement to fisheries management goals / compare with harvest & habitat management 4. Prioritize and select target species and stocks for enhancement 5. Assess economic and social benefits and costs of enhancement Stage 2: Research & Technology Development & Pilot Studies 6. Enhancement system designs suitable for fishery management objectives 7. Develop appropriate aquaculture systems and rearing practices 8. Use genetic resource management to avoid deleterious genetic effects 9. Use disease and health management 10. Ensure that released hatchery fish can be identified 11. Use an empirical process for defining optimal release strategies Stage 3: Operational Implementation & Adaptive Management 12. Devise effective governance arrangements 13. Define a fisheries management plan with clear goals, measures of success and decision rules 14. Assess and manage ecological impacts 15. Use adaptive management (Lorenzen, Leber, and Blankenship. 2010. Reviews in Fisheries Science 18(2):189-210)

Effect of Enhancements, harvest and habitat management should be modeled, a priori, and integrated into the decision making process (http://www.aquaticresources.org/pubs/EnhanceFish_Manual.pdf)

Genetic Management Is Essential Avoid transfer of exogenous alleles Avoid change in gene frequencies Avoid inbreeding and outbreeding depression

Virtually all aspects of enhancement research and management require the ability to identify released fish

Release Variables: Critical Uncertainties Critical Choices Managers of Hatchery Releases Need to Make Critical Choices Managers of Hatchery Releases Need to Make Tag type, tag placement, tagged proportion Acclimation at release site Size-at-release (SAR) Season and tidal timing Release habitat/ microhabitat Effects of interactions Release magnitude Thus, use of pilot studies and adaptive management to optimize release strategies is key to understanding effects and effectiveness and efficiencies Thus, use of pilot studies and adaptive management to optimize release strategies is key to understanding effects and effectiveness and efficiencies

Release Design Day 1: Stocked Acclimation pens Day 3: Released snook from acclimation pens & also Stocked non-acclimated snook NCONCMCCLNCL NCONCMCCLNCL Result: Survival Increased ~100% (Brennan, Darcy and Leber, 2006. J. Exp. Mar. Biol. Ecol. 16(1):1-9)

Acclimation effect on recapture rate Of hatchery-released snook

Reef Unit (no acclimation)

Netting Removed to Release Acclimated Fish

Red Snapper Recapture Rates at High Stocking Density Sites, Fall 2002

RECAPTURE FREQUENCY SUMMERFALLWINTER SEASON 100-130 mm 48-70 mm 70-100 mm n=172 n=210 n=155 Season: P < 0.007* SAR: P < 0.001* Interact.: P > 0.085 Pacific Threadfin in Hawaii Releases at Kaalaea Beach Leber, K. M., N. P. Brennan and S. M. Arce. 1998. Recruitment patterns of juvenile, cultured Pacific threadfin, Polydactylus sexfilis (Polynemidae), released along sandy marine shores in Hawaii. Bulletin of Marine Science 62(2):389-408.

RECAPTURE FREQUENCY SUMMERFALLWINTER SEASON 100-130 mm 48-70 mm 70-100 mm n=276 n=526 n=277 Seas: P < 0.002* SAR: P = 0.392 Inter.: P > 0.006* Pacific Threadfin in Hawaii Releases at Kahana Bay Leber, K. M., N. P. Brennan and S. M. Arce. 1998. Recruitment patterns of juvenile, cultured Pacific threadfin, Polydactylus sexfilis (Polynemidae), released along sandy marine shores in Hawaii. Bulletin of Marine Science 62(2):389-408.

Release Microhabitat has a Large Effect on Snook Survival; for example: Release Site (coded wire tag info) (>12 MONTHS AT SEA)

assess enhancement Effectiveness

Requires evaluation of hatchery-wild interactions at all three stages of developing enhancements

Late summer/fall abundance decline Late summer/fall abundance decline Late summer/fall abundance decline Late summer/fall abundance decline Post-release loss hatchery fish ~64-85% (Brennan, N.P., C.J. Walters and K.M. Leber. 1998. Rev. Fish. Sci. 16(1-3):228-241 ) 3 rd ISSESR

Adaptive Management is Crucial Recognized Production - Enhancement Management Dichotomy ReleaseStrategy AdaptiveStocking Production ImpactAssessment ManagementPlan IncreasedControl E.Eff. Loop P.Eff. Loop Production Oriented Enhancement Oriented (Leber, 2002. Advances in Marine SE: Shifting Emphasis to Theory & Accountability. In Stickney & McVey )

34 Hatchery Snook -- 6 when released Apr 1999 in Bowlees Creek Caught July 2004 in Bowlees Creek

Legacy from the Past Allure of a Quick Fix Allure of a Quick Fix If not implemented responsibly, enhancements may lull fishery managers into false confidence Isolation from the Fisheries Science Community Isolation from the Fisheries Science Community Often run with no connection to existing fishery management process, with hatcheries isolated and operating independent from stock assessment and fisheries monitoring programs (In: Leber, K.M., in press)

Enabling Factors for Expanding Successful Marine Enhancements Greater awareness among all stakeholders of the issues, pitfalls, progress and opportunities Greater awareness among all stakeholders of the issues, pitfalls, progress and opportunities Use of Adaptive management is critical for managing enhancement programs for success Use of Adaptive management is critical for managing enhancement programs for success Adapt the Responsible Approach to local circumstances Adapt the Responsible Approach to local circumstances Seek Assistance from established expertise in this field and the key associated fields Seek Assistance from established expertise in this field and the key associated fields (In: Leber, K.M., in press)

StockEnhancement.org/science/publications.html 65 Fisheries Enhancement Publications

Key Issues to Consider Is Enhancement needed? Which form of enhancement (restocking, stock enhancement or sea ranching)? Is Enhancement needed? Which form of enhancement (restocking, stock enhancement or sea ranching)? Have stock assessments been done to evaluate current status of the reef fishes and other species targeted for enhancement? This would greatly increase the capability of models to predict enhancement yields. Have stock assessments been done to evaluate current status of the reef fishes and other species targeted for enhancement? This would greatly increase the capability of models to predict enhancement yields. Adaptive management is critical for managing enhancement impacts for success is tagging and monitoring of stocking impact well integrated into enhancement management plan? Adaptive management is critical for managing enhancement impacts for success is tagging and monitoring of stocking impact well integrated into enhancement management plan? Is help needed to adapt the Responsible Approach to local circumstances Is help needed to adapt the Responsible Approach to local circumstances

theme 4. stock enhancement 1. introduction 2. us perspective on history, pitfalls and progress...

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